The research proposed is designed to enable a substantial improvement in human heart preservation prior to transplantation. The model involves preservation of canine hearts and evaluation by transplantation and functional assessment over a 6-hour observation period following weaning from cardiopulmonary bypass. Preliminary results indicate excellent recovery of 5 out of 5 hearts after preservation for 40 hours. We propose the development of a very simple yet highly effective preservation device that should enable clinicians to employ the new preservation method without difficulty, safety concerns, or substantial expense. Phase I primarily seeks to show that unattended use of the device yields preservation quality that equals what has been obtained previously with manual methods. Phase II would further employ the device to fully optimize this highly promising method in preparation for human clinical trials, which can be done at the Research Institution when warranted. It is now accepted that excellent matching between donors and recipients can result in at least a 50 percent increase in survival rate 10 years after transplantation. The ability to extend human clinical cardiac preservation to 40 hours would allow transcontinental prospective matching, with expected substantial gains in clinical outcome for potentially thousands of heart transplants recipients. PROPOSED COMMERCIAL APPLICATION: Potential commercial applications include marketing of devices, disposables, protocols, software, and upgrades used in the preservation of hearts, other organs, and engineered tissues for transplantation.